Steam the broccoli in a large steamer basket over simmering water, until bright green and tender. Season with salt and pepper and set aside.
Cook pasta in a large pot of boiling water according to package directions. Drain and set aside.
Heat a tablespoon of the olive oil in a large, deep skillet over medium heat. Add the shallot and garlic and sauté until it turns soft and transluscent. Add the broccoli and parsley, and cook until the parsley is wilted. Add the lemon juice, and simmer, stirring occasionally, for 2 minutes.
Transfer the mixture the bowl of a food processor. Add half of the feta, and 1/4 cup of water. Pulse until well-incorporated. Drizzle in the last tablespoon of olive oil, and blend, adding more water a tablespoon at a time if neccesary, until it's as smooth as you'd like. Taste, and add more salt and pepper if needed. Return to the skillet, and add the cooked pasta, tossing until the pasta is well coated. Heat over low heat until heated through, if needed. Serve hot, topped with remaining feta.